Thermally Stable Polymer Gel Electrolytes Composed of Branched Polyimide and Ionic Liquid/Zwitterion Mixture Prepared by In Situ Polycondensation

摘要

Branched polyimide was synthesized by in situ polycondensation of 4,4'-oxydianiline,pyromellitic dianhydride,and 1,3,5-tri(4-aminophenyl)benzene in ionic liquid/zwitterion mixture.Compatibility between network and ionic liquids is important to keep gel shape and ionic conductivity.Only 6.0 wt% of polyimide was enough to keep gel state without phase separation or leakage.The obtained polyimide gel showed excellent thermal stability with decomposition temperature of above 300°C,low glass-transition temperature,and stable ion conduction in a wide temperature range.